Technical Field
Embodiments of the present disclosure are directed to semiconductor packages and methods of forming same.
Description of the Related Art
A lead frame semiconductor package is often assembled and molded as a group of semiconductor packages in a lead frame strip. As is well known in the art, the lead frame strip includes a plurality of die pads and leads that are connected together by connecting bars. The die pads of the lead frame strip may be arranged in a single line or matrix.
After assembling the packages, the individual packages are separated from each other by a singulation process. The singulation process also removes the connecting bars, thereby electrically isolating the leads and the die pads with each assembled package. The singulation process, which typically involves sawing, laser cutting, or punching can cause problems. For instance, stresses may be induced into the packages during one or more of these singulation processes. The induced stresses may cause cracks in the molding material of the packages and can cause leads to detach from the molding material, thereby affecting the reliability of the package.
Additionally, saw blades, particularly worn saw blades, may cause leads to smear along the molding material. Adjacent leads that smear together can result in an unwanted electrical coupling of adjacent leads.
Another problem encountered during the singulation process is due to warpage of the molded lead frame strip. That is, the lead frame strip may have warpage induced during the molding process. The warpage may make it difficult for the lead strip to maintain a vacuum on a holding device for the singulation process.
Finally, sawing, laser cutting, and punching, in general, utilize patterned processing steps for separating the packages. For instance, the each of these processes utilize a grid pattern for aligning the lead frame strip, such as dicing streets, with a laser, saw blade, or punching mechanism. In that regard, mapping software or visual tooling is typically required in an automated singulation tool. This can make the singulation process expensive and time consuming.